measurement-scripts/format_gps_to_csv.py

#!/usr/bin/env python3
from argparse import ArgumentParser
from time import sleep

import pandas as pd

import csv
from datetime import datetime
import math

if __name__ == "__main__":
    parser = ArgumentParser()
    parser.add_argument("-f", "--file", required=True, help="NMEA file.")

    args = parser.parse_args()
    epoch = datetime.utcfromtimestamp(0)

    outputfile = open(args.file.replace("nmea", "csv"), "w")
    writer = csv.writer(outputfile, delimiter=",", lineterminator="\n")
    writer.writerow(
        ["datetime", "time_epoch", "latitude", "longitude", "speed (knots)", "systime_epoch"]
    )
    csv_string = ""

    for line in open(args.file, "r").readlines():
        if line.startswith("$GPRMC"):
            row = line.split(",")

            time = row[1]
            lat = row[3]
            lat_direction = row[4]
            lon = row[5]
            lon_direction = row[6]
            speed = row[7]
            date = row[9]
            systime_epoch = row[13] if len(row) < 14 else 0

            date_and_time = datetime.strptime(date + " " + time, "%d%m%y %H%M%S.%f")
            time_since_epoch = date_and_time.timestamp()
            date_and_time = date_and_time.strftime("%y-%m-%d %H:%M:%S.%f")  # [:-3]

            lat = round(math.floor(float(lat) / 100) + (float(lat) % 100) / 60, 6)
            if lat_direction == "S":
                lat = lat * -1

            lon = round(math.floor(float(lon) / 100) + (float(lon) % 100) / 60, 6)
            if lon_direction == "W":
                lon = lon * -1
            writer.writerow([date_and_time, time_since_epoch, lat, lon, speed, systime_epoch])
    outputfile.close()
    sleep(1)

    gps_df = pd.read_csv(args.file.replace("nmea", "csv"))
    #gps_df["datetime"] = pd.to_datetime(
    #    gps_df["systime_epoch"].apply(lambda x: datetime.fromtimestamp(x))
    #)
    gps_df.to_csv(args.file.replace("nmea", "csv"))